DANIEL RIVERA darted frenetically between slow-moving tourists who’d wandered cluelessly onto Canal Street, and hoped no one would care about the mask concealing his face.

“You never know. You never know,” Rivera, a Philippines native, muttered into the hospital-grade paper, while trying to stuff an advertising flier into my hand.

Yesterday, a sunny, noontime walk along Chinatown’s main drag – normally an endurance test against blasting car horns, violent smells and combative pedestrians – had the unsettling feel of a stroll in the suburbs.

Blocks where usually you can’t see a speck of pavement for all the people resembled gaping boulevards.

Stalls hawking “genuine” Prada purses for $20 – $10 if you start to walk away – were nearly customer-free. And proprietors of sparsely filled restaurants shoved patrons to front tables, trying to make their joints look invitingly busy to the few passers-by.

Terrorism couldn’t do it. Anthrax didn’t touch it. War couldn’t stop it. But now something has come along to paralyze some of the most crowded streets of this city. But only Rivera, with his mask, seemed willing to say the word aloud: SARS.

“I have a cough. At night, I’m sneezing, too,” Rivera confessed, causing a man poised to take one of his fliers to turn on his heel.

A lot of people don’t want to take a chance that the guy waiting tables, the woman in the shop, the kid on the scooter, is a modern-day Typhoid Mary.

The rule of thumb in Chinatown yesterday seemed to be this: The more exotic your business, the harder you’re hit. Just a handful of shoppers braved the eel tanks of the normally bustling Dynasty Supermarket.

“Even the locals, they buy what they need and go home – or they stay away and go to the Pathmark,” said manager Louie Cham.

In three weeks, All Health Pharmacy has sold “thousands” of paper masks, said owner Wei Lee. The number sold “depends on the headline. If the news says, ’10 die!’ you sell a lot more.”

At the United Trading & Fletcher wig shop, a dummy wore a mask. Business is half what it was in the lethargic, post-9/11 days, said Oanfa Quan, whose family owns the store.

“I carry a mask with me,” she confesses. “You have it in your bag, just in case.”

But Wendy Zheng, 23, was glad to be in Chinatown. The student is postponing her return home to Beijing as long as she can.

“In my city, there’s been two deaths already,” she said. “All the markets are closed down.”